Physics & Astronomy Colloquium: Adam Riess

Description

Dr. Adam Riess, a Bloomberg Distinguished Professor of Physics and Astronomy and of Earth and Planetary Sciences at Johns Hopkins University, will give a talk entitled "A New Measurement of the Expansion rate of the Universe: Hints of New Physics?" for the Physics & Astronomy Colloquium.

Dr. Riess won the 2011 Nobel Prize in Physics.

Abstract:

The Hubble constant remains one of the most important parameters in the cosmological model, setting the size and age scales of the Universe. Present uncertainties in the cosmological model including the nature of dark energy, the properties of neutrinos and the scale of departures from flat geometry can be constrained by measurements of the Hubble constant made to higher precision than was possible with the first generations of Hubble Telescope instruments. A streamlined distance ladder constructed from infrared observations of Cepheids and type Ia supernovae with ruthless attention paid to systematics now provide <2% precision and offer the means to do much better. By steadily improving the precision and accuracy of the Hubble constant, we now see evidence for significant deviations from the standard model, referred to as LambdaCDM, and thus the exciting chance, if true, of discovering new fundamental physics such as exotic dark energy, a new relativistic particle, or a small curvature to name a few possibilities. I will review recent and expected progress.